Abstract Background Sexual minority (i.e., lesbian, gay, and bisexual [LGB], and other non-heterosexual) individuals are more likely to use mental health services than heterosexuals; however, evidence is scarce about factors contributing to this difference. Methods This study uses longitudinal data from a population-based sample of young adults (aged 18- 36) in Sweden (N = 1,137). We use mediation analysis to examine whether common mental health symptoms (i.e., depressive, anxiety and social anxiety symptoms, suicidality, and alcohol use) mediate sexual orientation differences in mental health services use; and to understand whether adding general stressors (i.e., low social support, loneliness, and perceived stress) to these models increases the total effect explained. Afterwards, we use logistic regression models to understand how minority-specific stressors (e.g., family reaction and dimensions of sexual minority identity) predict mental health service use among sexual minority individuals (N = 498), adjusting for common mental health symptoms. Results Common mental health symptoms only partially mediate the associations and the direct effect for sexual orientation remain significant (β = 0.11, p < 0.01). Adding general stressors to these models only slightly increase the total effect explained and the direct effect remained significant (β = 0.11, p < 0.01). Among sexual minority individuals, after adjusting for common mental health symptoms, a difficult process of coming out (β = 0.12, p < 0.05) and negative family reaction towards one’s sexual orientation (β = 0.15, p < 0.05) predicted use of mental health services. Conclusions Overall, these results show that minority-specific stressors contribute to help-seeking behaviours among sexual minority individuals, regardless of psychiatric morbidity, highlighting the potential role of mental health services empowering sexual minority individuals to cope with minority stress.